Fig. 1: Device layout and qubit frequency calibrations.
From: Tracking spin qubit frequency variations over 912 days
a, b False-colored scanning electron microscope images of two nominally identical devices to the ones used in the experiments. The linear device hosts six qubits, whilst the 2 × 2 device hosts four qubits. In both devices, the electron spin qubits reside beneath the plunger gates (P) as indicated by the white dashed circles. The barrier gates (B) are used to tune the tunnel coupling between adjacent dots and to the reservoirs. Screening gates (colored pink and with their contours indicated by dashed black lines) are used for extra confinement of the dots. The screening gate located nearest to the dots is also used to deliver microwave signals for EDSR driving. c Example of resonance frequency calibration scans for all six qubits in the linear device taken on the same day.
